DE60131802T2 - Fixing element, fixing arrangement and image forming apparatus - Google Patents

Description

BACKGROUND OF THE INVENTION

Field of the invention

These The invention relates to a fixing element of a fixing structure, used in an image forming apparatus which is an image forming method such as electrophotography or electrostatic recording. In particular, this invention relates to a fixing element, that in a heat fixation setup is used by an unfixed toner image on a recording material (such as a transfer material, printing paper, photosensitive paper or paper for electrostatic recording) is generated and carried by a transmission system or a Direct system in an image processing section by heat setting is treated to create a fixed image. It refers also to a Fixieraufbau with such a fixing and an image forming apparatus with the fixing structure.

State of the art

Conventionally, in fixing structures provided in an image forming apparatus using an image forming method such as electrophotography or electrostatic recording, heat fixing constructions in which a recording material (hereinafter also referred to as "transfer material") holding an unfixed image thereover are often used A gap is formed between a fixing roller and a pressing roller which are rotated in press contact with each other to fix the toner image on the recording material. An example of an image forming apparatus having a conventional heat fixing structure is shown in FIG 5 shown.

In the in 5 The device shown comprises a fixing roller 10 which is a fixing member having a heating element, a hollow mandrel made of aluminum, and a heating element halogen lamp is provided inside the mandrel. From the inside of the hollow mandrel, a recording material is heated at a temperature high enough to cause the toner (toner image) held thereon to be melted by supplying electric power from a power source (not shown).

On the circumference of the hollow mandrel becomes a release layer, the one Material such as a polytetrafluoroethylene copolymer (PTFE) or a perfluoroalkoxytetrafluoroethylene copolymer (PFA) is produced, the re releasability and durability across from Heat has excellent behavior. The release layer is on the hollow thorn by coating from its surface with a material that is in a tube is formed, or by its coating with a material by means of electrostatic Spray, Dip coating or the like produced.

A However, such a fixing roller has a problem that it is a phenomenon of the electrostatic offset in which the on the Recording material held electrostatically transferred to the fixing roller which leads to a lower image quality level.

Because of a triboelectric charging, which is located between the recording material and the fixing roller occurs, or because of electrical transfer charges, which accumulate on the recording material becomes an electric Field generated by the toner on the recording material is attracted to the fixing roller, so that a part of the toner image transferred to the fuser roller becomes. Once the fuser roller is rotated, the on transmitted this way Toner is fixed to the recording material to become a ghost to become the picture. This will be "electrostatic Called offset ".

Of the electrostatic offset is roughly divided into two types, offset over the the whole area and release offset. The offset over the entire area is a phenomenon wherein the recording material and the fixing element such as the fuser over each other give a triboelectric charge electrical charges and take, to continuously create an offset electric field, and the offset appears continuously over the entire image area. Meanwhile is the release offset a phenomenon in which the recording material hops at its rear end to to come into firm contact with the fuser roller when the rear End of the recording material passes through the Fixieraufbau, so that it leaves a potential history linearly on the fixing roller in its longitudinal direction, which Potential causes an offset, and appears in the picture Offset linear in the main direction of scanning. Thus, the two distinguishable.

Around To prevent such electrostatic offsets becomes the potential the fixing roller in a conventional Device controlled at a constant value. More precisely, if a negatively chargeable toner is used, the fuser roll becomes subjected to antistatic treatment to not positively charged or is set electrically conductive and grounded, to have a potential of 0V.

In In an experiment, a surface potential of the surface layer became such a fixing roller with a surface potentiometer during the feeding measured from paper to find out that the surface layer even while of feeding of paper was charged only at a few tens of volts, on this The antistatic effect was confirmed.

Meanwhile, as the image quality and the process speed of the electrophotographic apparatus have been increased in recent years, a phenomenon called "smeared image trailing edges" has clearly occurred in which a part of horizontal line images propagate to the rear end side thereof to be broken when the horizontal line images are fixed The cause of such a phenomenon of smeared image with edges with banding is presumably mainly the pressure from inside The phenomenon of smeared image with edges with banding will now be referred to with reference to FIG 6 described.

As in 6 shown, the steam flowing at a space between a fuser roller 10 and a recording material 21 shoots out in the direction of an arrow and gets between the fuser roller 10 , the recording material 21 and a toner image 41 compressed to the toner image 41 mess with each other.

As one of the countermeasures for the phenomenon of smeared image with edges with banding, it is proposed to provide means for applying a bias to the fixing roller 10 provide. 7 shows an example of an arrangement provided with such a bias applying device (or bias power source) 12 as an example of the countermeasures for the smeared image with edges with banding.

As in 7 shown, has a fixing roller 10 a fuser roll mandrel 10a formed in a hollow roll and a release layer 10b covering the circumference of the fixing roller mandrel 10a covered. On the fuser roll mandrel 10a becomes a DC voltage of about 500 to 1000 V from the bias power source 12 created. Here, a resistance element (not shown) of several MΩ to several dozen MΩ as a safety resistance to the bias power source 12 and the fuser roll mandrel 10a provided.

By means of an electric field generated by this bias, the toner image on the recording material 21 electrostatically fixed on the recording material 21 held when the recording material 21 in a fixing gap 31 crashes. In this state, the recording material 21 with the toner image between the fuser roll 10 and a press roll 11 held and transported through. Thus, occurrence of a smeared image having edges with streaking on the recording material 21 can be avoided even if the flow of steam is generated as described above.

In the arrangement where the bias applying means is provided as a countermeasure to the smeared image having edges with banding, it is important to have an electric field beyond the toner image 41 and the back of the recording material 21 through the recording material 21 to generate what electric field the toner to the part of the recording material 21 attracts. Accordingly, in such an arrangement, a transport roller (not shown) serving as a contact member is provided with the recording material 21 comes into contact, immediately behind the fixing gap 31 provided, and this roller is set electrically conductive and grounded, so that at the fixing roller 11 applied voltage an electric current through the recording material 21 caused the electric field beyond the toner image 41 and the back of the recording material 21 to create.

Here, each too low resistance of the fixing roller 10 cause an increase in the voltage assigned to the safety resistor to lower the voltage resulting in the formation of the electric field beyond the fuser roller 10 and the back of the recording material 21 so that the effect of avoiding a smeared image with edges with banding is reduced that can.

In controlling the resistance values of the fixing roller 10 By dispersing carbon or a charge controlling agent therein as conventionally carried out, the resistances of the fixing roller may be varied depending on the viscosity of a coating solution used when the fixing roller 10 whose pH, the state of dispersion of the carbon or the charge controlling agent therein and their changes over time change. Therefore, it was not easy, the resistance values of the fixing roller 10 at a constant value.

In addition, even if carbon in the fuser roller 10 is dispersed in a small amount, the fixing roller 10 not simply made to have a low surface resistance. Accordingly, in order to make their surface resistance small enough so that the effect of avoiding the electrostatic offset can be achieved, the carbon must be dispersed in a large amount. However, dispersing a large amount of carbon can cause the fuser roll 10 has a very low volume resistance. Therefore, an effect of avoiding smeared image with edges with banding can not be achieved, and it has been difficult to ensure a sufficient image quality.

As in the disclosed Japanese Patent Application No. 2000-19879 discloses a heat fixing roller is proposed in which the release layer is formed in a multi-layer and a filler is dispersed in each layer. In such an arrangement, the fixing roller can be made to have a suitable volume resistance, but can not be easily made to have a low surface resistance. Thus, there is room for further improvement in resistance to electrostatic offset (ie, anti-offset properties). In addition, a filler having a low powder resistance may cause a large change in volume resistivity, making it difficult to control the volume resistivity.

Accordingly, it has long been desired to provide a method by which the release layer on the surface of the fixing roller 10 is made to have only a small surface resistance without being made to have a low volume resistivity.

US 5,561,511 discloses a fuser member including, inter alia, a release layer composed of PTFE resin containing a low-resistance material, e.g. Carbon black, carbon fiber, graphite whisker, silicon carbide fiber, silicon carbide whisker, a metal oxide such as titanium dioxide or nickel in an amount of 20-40%, and a PFA resin in an amount of 5-15%. Further, in this document, it is mentioned that the release layer has a volume resistivity of 10 ¹¹ -10 ¹⁴ Ω · cm.

US 5,717,988 discloses a fuser roll having a coated offset-preventing layer comprising a fluororesin compound of PTFE resin and PFA resin, and either a conductive double-shell hollow substance as a filler in which the inner shell is made of amorphous silica, and the outer shell substantially is composed of conductive oxide, or a whisker-like monocrystal of potassium titanate as a filler.

EP 0 277 651 A2 shows a hydrophilic surface treatment of filler particles (page 8, lines 1-7, Table 2) to adjust the resistance of the particles.

Other fixings are off US 6,041,210 . US 5,995,796 and EP 0 828 201 A1 known.

SUMMARY OF THE INVENTION

A The object of the present invention is to provide a fixing element, that solves the above problems a Fixieraufbau with such a fixing element and an image-forming Device with the fixing structure.

A Another object of the present invention is a fixing that can be made continuously to one low surface resistance to possess, and the superior anti-offset properties and durability across from a smeared image with edges having a banding, a Fixieraufbau with such Fixing element and an image-forming device with the Fixieraufbau.

Around To achieve the above objects is the present invention a fixing element according to claim 1 or 2 ready.

preferred embodiments are in the dependent claims Are defined.

BRIEF DESCRIPTION OF THE DRAWINGS

1 Fig. 12 is a schematic side view of an image forming apparatus in a first example of the present invention.

2 Fig. 10 is a schematic view of a fixing structure in the first example of the present invention.

3 Fig. 12 is a schematic view showing a film-type fixing structure in a third example of the present invention.

4 Fig. 12 is a schematic sectional view of a fixing film in the third example of the present invention.

5 Fig. 10 is a schematic view showing an example of a conventional image forming apparatus.

6 illustrates the mechanism by which a smeared image with edges with banding occurs.

7 Fig. 10 is a schematic view showing another example of a fixing structure in the conventional image forming apparatus.

8th illustrates the mechanism by which the surface potential of a fixing roller in the first example is lowered.

9 Fig. 12 is a schematic sectional view of a fixing roller in a third comparative example of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The fixing member of the present invention comprises a conductive layer and a release layer formed on the conductive layer. In the release layer, medium resistance particles and / or intermediate resistance whiskers are dispersed. The releasing layer has a surface resistance of 1.0 × 10 ⁸ Ω or less, and a volume resistivity of 1.0 × 10 ⁸ Ωcm or above.

in the Fixing element of the present invention serves the part of the particles medium resistance and / or medium resistance whisker, contained in the release layer as leaks, the surface resistance of the fixing element to a degree within a specific range can minimize and also can not make its volume resistance unnecessarily low to maintain it within a specific range without dispersing a conductive Agent or antistatic agent in the release layer of the Fixing assembly. Thus, it becomes possible a fixing element with superior anti-offset properties and durability across from a smeared image with edges to provide with banding.

The medium-resistance particles and the intermediate-resistance whiskers may have a powder resistance of 1.0 × 10 ¹ to 1.0 × 10 ¹² Ωcm. This can provide a fuser member with further superior anti-offset properties and resistance to smeared image with streaked edges. Also, this resistance is preferred to control the resistance values of the release layer.

The intermediate resistance particles and the intermediate resistance whiskers may have a powder resistance of 1.0 × 10 ³ to 1.0 × 10 ⁹ Ωcm. This may provide a fuser member having further improved anti-offset properties and resistance to smeared image with streaked edges. Also, this resistance is further preferred to the resistance values of the release to control the shift.

The Medium resistance particles and medium whiskers Can resist Have surfaces, which have been exposed to a hydrophilic treatment. This makes possible, that ions on the particle surfaces and their surroundings are captured to the surface resistance more efficient, and is further preferred to both Anti-offset properties, as well as resistance to one smeared image with edges to achieve with banding.

The Medium resistance whiskers can whisker a metal oxide be. This can improve the strength of the release layer of the fixing element improve and at the same time the resistance to wear improve. Thus, a fixing element with superior anti-offset properties and durability across from a smeared image with edges be provided with banding.

The Medium resistance whiskers can be metal oxide whiskers whose surfaces have been exposed to a hydrophilic treatment. This can be one Fixing element with superior Anti-offset properties and resistance to one smeared image with edges provide with banding.

The Particulate particles may be titanium oxide particles their surfaces have been exposed to a hydrophilic treatment. This can be one Fixing element with superior Anti-offset properties and durability across from a smeared image with edges provide with banding.

The Medium resistance particles and / or medium whiskers Can resist in the release layer in a total amount of 5 to 50% by weight based on the weight of the release layer. This is preferred to provide a release layer with appropriate surface resistivity and to make volume resistance when the fixing element with superior Anti-offset properties and resistance across from a smeared image with edges is provided with banding.

The Release layer may be one or both of the medium particles Resistance and the medium resistance whisker and a fluororesin contain. This is preferred to provide a release layer with superior Release properties and resistance to heat, if a fuser that has both anti-offset properties as also resistance to one smeared image with edges achieved with banding is provided.

The release layer may be formed to have a surface resistance of 1.0 × 10 ³ to 1 × 10 ⁸ Ω and a volume resistivity of 1.0 × 10 ⁸ to 1 × 10 ¹⁵ Ωcm. This is further preferred to provide the fuser which has achieved both anti-offset properties and resistance to a smeared image with fringing edges.

The Release layer may have a layer thickness of 1 to 45 microns. this makes possible a generation of a release layer with well balanced mechanical Strength and heat transfer properties, when the fuser, which has both anti-offset properties as also resistance across from a smeared image with edges achieved with banding is provided.

The Release layer may have a layer thickness of 3 to 30 microns. This is further preferred to provide a release layer with good balanced mechanical strength and heat transfer properties form when the fixing element, both anti-offset properties as also resistance across from a smeared image with edges achieved with banding is provided.

The Fixing element may be formed in the form of a roller. this will preferred to a higher process speed reach the device when the fixing element, both Anti-offset properties as well as resistance to one smeared image with edges achieved with banding is provided.

The Fixing element may be formed in the form of a belt or a film be. This is preferable to a fixing member having higher heat transfer efficiency provide when the fixing element that has both anti-offset properties as well as durability across from a smeared image with edges achieved with banding is provided.

According to the fixing structure of the present invention, be the above-described fixing it is possible to achieve both anti-offset properties and resistance to a smeared image with banding edges.

In the Fixieraufbau can a potential difference between the release layer and the conductive layer to be provided. This is further preferred to provide a fixation structure, which has both anti-offset properties and durability across from a smeared image with edges with banding has been achieved.

According to the image-forming Apparatus of the present invention which is as described above Has fixation structure, it becomes possible both anti-offset properties as well as durability across from a smeared image with edges to achieve with banding.

embodiments The present invention will be described below in more detail.

The Fixing element of the present invention is a fixing with a release layer in which one or both of particles with medium resistance and whisker with medium resistance so are dispersed, that they have an insulation failure at the surface of Can cause release layer, which with the recording material at the time of fixing comes into contact with leaks in the release layer so that the surface potential the release layer to a sufficient extent To obtain anti-offset effect, and also to the volume resistance maintain the release layer at a given value or above, for durability across from a smeared image with edges with banding to ensure.

Accordingly exist with regard to its shape no special restrictions, as long as it is an element that is in with the recording material Contact comes to unfixed toner images on the recording material to be held, to fix. For example, it may be a fixing element whose release layer is in synchronism with the recording material moves, or may be a fixing, its release layer stationary is fixed, and in sliding Contact with the recording material comes. Such a fixing element may have any shape, including, for example, the shape a roller, the shape of a belt and the shape of a film. Consequently Any shape conventionally used as the shape, which can accept the fixing, is known. A fixing element The shape of a roll can have a relatively large heat capacity and is advantageous for a higher process speed. A fixing member having the shape of a belt or film is advantageous for the Improvement in the energy efficiency of the device due to a Improvement in heat transfer efficiency.

What the conductive one Regarding shift, there are no special restrictions as long as you have a good conductivity Has. It can be a layer that is in a fixed shape using a conductive Material is formed, or can be a layer on one Substrate (conductive or not conductive) a known means such as vacuum deposition, dip coating or spray is formed. The conductive Material that is such a conductive Layer can be exemplified by non-magnetic conductive Materials like aluminum, stainless steel and copper, magnetically conductive materials like Iron, and conductive Plastics. With the "layer" referred to here is taken, a layer is meant to be a superposition forms, and there are no special form Restrictions.

In the release layer may include one or both of the particles medium resistance and the intermediate resistance whisker dispersed be, and this layer is the outermost layer, those with the recording material at the time of fixing in Contact is coming. Accordingly, the Release layer preferably good releasability over the Recording material and the formed on the recording material Have toner image. To form such a release layer, Conventionally known resin or rubber may be used. The resin or rubber may be exemplified by fluororesins or fluororubbers with good releasability such as polytetrafluoroethylene copolymers and perfluoroalkoxytetrafluoroethylene copolymers. Each of these resins or rubbers may be used alone or in combination be used by two or more species.

The release layer may preferably have a layer thickness of 1 to 45 μm, and more preferably 3 to 30 μm, from the viewpoint of durability and fixing structure heat efficiency. When the releasing layer has a layer thickness of less than 1 μm, the releasing layer tends to be abraded or peeled off as a result of the repetition of paper feeding. This is not preferred given the durability. On the other hand, when the release layer has a layer thickness, the greater than 45 μm, the release layer may function as a thermal insulating layer. This is not preferred in view of the heat efficiency. The layer thickness of the release layer can be controlled during the generation of the layer. The layer thickness of the release layer produced can, for. B. be measured with a coating thickness gauge such as a micrometer.

Regarding the Medium resistance particles and medium whiskers Resistance are not particularly limited as long as they are particles or whiskers that cause an insulation failure at the surface of the Release layer during of charging, to form leaks at which the particles with medium Resistance and / or the middle resistance whiskers as nuclei stand. Such medium-resistance particles and medium-sized whiskers Can resist Metal oxides and ceramics. More precisely, they can exemplified are represented by titanium oxide, zinc oxide, tin oxide, indium oxide, aluminum oxide, Barium titanate, silicon carbide, silica, glass beads and carbon fluoride. The medium-resistance particles can be any Have shape, such as a spherical one or amorphous. The medium resistance whiskers can also have any shape such as a needle-shaped, tetrapod, two-dimensional or three-dimensional.

The intermediate resistance particles and the intermediate resistance whiskers may preferably have a powder resistance of 1.0 × 10 ¹ to 1.0 × 10 ¹² Ωcm, and more preferably from 1.0 × 10 ³ to 1.0 × 10 ⁹ Ωcm , This is advantageous from the viewpoint of efficiently forming the leakages and controlling the volume resistivity and the surface resistance independently. When the middle resistance particles and the intermediate resistance whiskers have a powder resistance less than 1 x 10 ¹ Ωcm, such as the conductive particles such as carbon, the release layer tends to have a very low volume resistivity as the particles are dispersed in an amount large enough to lower the surface resistance. This is not preferred in view of resistance to smeared image with edges with banding. If the middle resistance particles and the middle resistance whiskers have a powder resistance higher than 1.0 × 10 ¹² Ωcm, they may have too little difference in resistance from that of a release layer resin to cause the insulation failure in the release layer so that leaks can not be efficiently produced, and therefore, the fixing roller can not be made to have a sufficiently low surface resistance. This is not preferred in view of the anti-offset properties.

The powder resistance of the medium-resistance particles and the intermediate-resistance whisker is determined by measuring the DC resistance of a powder sample which has been formed into a disk-like compressed powder at a pressure of 100 kg / cm ² (diameter: 18 mm, thickness: 3 mm ), and calculated from the following expression. Powder resistance = measured value × 2.54 / thickness (In the expression, 2.54 denotes an electrode constant, and the unit of the thickness is cm.)

The Medium resistance particles and medium whiskers Can resist preferably those having a primary or secondary particle diameter be bigger than that the thickness of the release layer is around the surface potential reduce the release layer. The particles with medium Resistance and the medium resistance whiskers can too preferably have a particle shape that deforms more is considered a spherical one Particles, and can preferably z. B. an aspect ratio, the ratio of Length to Width of a particle (length / width ratio) of 10 to 40 have. If they have an aspect ratio of less than 10, can they have a small dominance over spherical Have particles. If you have an aspect ratio of more than 40, can the whiskers are destroyed at the time of dispersion, what makes it difficult, the surface potential of the fixing in a good efficiency to lower.

The intermediate resistance particles and the intermediate resistance whiskers may be those whose surfaces have been subjected to hydrophilic treatment. This more effectively brings about the effect of lowering the surface resistance of the release layer. In this hydrophilic treatment, such as that conventionally carried out on ordinary pigment titanium oxide or ultrafine titanium oxide particles, their surfaces may be coated with a hydrous oxide and / or an oxide of at least one selected from the group consisting of Al, Si, Zr, Sn , Ti and Zn, are coated. Their surfaces may also be coated with an organic material of at least one selected from the group consisting of a silicon compound and a polyol compound. Likewise, she can, as at a method for hydrophilic treatment, a physical treatment such as a plasma treatment, an ion beam treatment or an ultraviolet irradiation treatment, and a chemical treatment such as treatment with chemicals using an acid or a base and a treatment with solvents by using an organic solvent. In the present invention, two or more of these hydrophilic treatment methods may be used in combination.

When Whisker with medium resistance will use whiskers of metal oxides from the standpoint of strength and of Powder resistance of the medium resistance whiskers and the Shape that satisfies the above aspect ratio is preferable. The usage of whiskers of metal oxides exposed to the hydrophilic treatment is further from the viewpoint of degrading the surface resistivity with good efficiency preferred.

The Release layer may be without any particular limitation by any method be produced as long as a release layer with a preferred Layer thickness on the conductive Layer can be generated. It can be achieved by coating the conductive layer with a sheet-like or tubular release layer or by binding the latter to the former. alternative can it by a conventional known coating such as electrostatic spraying or Dip coating, or formed by a similar coating become.

The surface resistance and the volume resistivity of the release layer may differ depending on the types of the resin or rubber and the average resistance particles used and the amount in which the intermediate resistance particles are dispersed. Accordingly, when the releasing layer is formed, it is preferable to appropriately determine the preferable combination and blending amount, according to the kind of the resin or rubber, the kind (s) of the middle resistance particles used and / or the middle resistance whiskers, and the size and particle shape of the middle-resistance particles and / or intermediate-resistance whisker used to form the release layer so as to have preferable resistances, ie, the surface resistance of 1.0 × 10 ⁸ Ω or less, and the volume resistivity 1.0 × 10 ⁸ Ωcm or above.

The Medium resistance particles and / or medium whiskers Can resist in the release layer, preferably in an amount from From 5 to 50% by weight, and more preferably from 10 to 40% by weight, total, based on the weight of the release layer, dispersed be. If the particles with medium resistance and / or the whiskers having moderate resistance dispersed in an amount that is more As the above upper limit, the leaks are in the Number so high that they not only greatly affect the surface resistance, but also the volume resistance to a reduction in the volume resistance to cause. This is from the point of view of resistance to one smeared image with edges not preferred with banding. In addition, the release layer low surface properties have a tendency to cause toner adhesion. This will, also from the point of view of anti-offset properties, not prefers. If, on the other hand, the medium-resistance particles and / or the intermediate resistance whiskers are dispersed in an amount which is less than the above lower limit, can leaks are not sufficiently generated and the release layer can not be made to have a low surface resistance exhibit. This is under the aspect of anti-offset properties not preferred.

If in the present invention, the release layer is formed, can other materials such as carbon and conductive particles in a small Quantity can be mixed in such a range that they, for example Do not reduce the volume resistance extremely.

According to the release layer described above, since the surface resistance can be made lower than the volume resistivity in the release layer, the above-described phenomenon of offset can be avoided. In this case, the release layer may have a surface resistance of 1.0 × 10 ⁸ Ω or less, and preferably from 1.0 × 10 ³ to 1.0 × 10 ⁸ Ω. Also, since the volume resistivity in the release layer can be made higher than the surface resistance, the above-described blurred image having edges with banding can be avoided. In this case, the release layer may have a volume resistivity of 1.0 × 10 ⁸ Ωcm or above, and preferably from 1.0 × 10 ⁸ to 1.0 × 10 ¹⁵ Ωcm. If the surface resistance and the volume resistivity of the release layer deviate from the above state, it may be difficult to avoid at least one of the offset and the smeared image with edges with banding, so that good quality images can be obtained only with difficulty.

In The surface resistance of the present invention is the value of Resistance between two opposite Sides of a square, each side in a unit length (1 cm) has meant; the square is assumed on the release layer surface. The unit of surface resistance becomes ordinary in ohms per square (Ω / square) specified. However, in the present invention it is referred to as Ohms (Ω) according to JIS K6911 expressed.

Of the Volume resistance is also the value of the resistance between two opposite Sides of a cube, each side having a unit length (1 cm); the cube becomes assumed inside the release layer. With reference to the Unit is expressed as the ohmic centimeter (Ωcm).

Of the surface resistivity and the volume resistivity of the release layer may be, for example be measured in the following manner: using a circular electrode with a disc-like Main electrode and a ring electrode surrounding the main electrode, to leave a distance of about 9.5 mm, a preceding prepared sample by forming a release layer over one Polyethylene terephthalate (PET) film to this circular electrode Contact-bound to take a measurement with a resistance meter (4329 A, manufactured by Hewlett-Packard Co.) in an environment of 23 ° C and 600 humidity using a voltage of 10V across from to perform the main electrode and the ring electrode.

Of the Fixieraufbau the present invention is a unit with the Fixing element described above and a pressing element, wherein a A recording material having an unfixed toner image formed thereover by a generated by mutual pressing contact of these elements fixing gap is pushed to the unfixed toner image to fix on the recording material as a fixed image.

Of the Fixieraufbau can have any shape without any particular restriction, as long as he has the unfixed toner image on the recording material can fix. He can apply a system in which a bias at the time of fixing as described above is, or a conventionally known Fixing system such as a heat roller fixing, fixing using a film or pressure fixing, or a fixation system that combines some of these fixation systems become.

In addition to the fixing element and the pressing element of the Fixieraufbau more Have devices for each applicable fixing system are suitable. Such devices can for example, a heating element (a heating resistor) for causing the toner is attached to the recording material at the time of fixing adheres by melting, a current source for applying the bias voltage, a resistance element for controlling the application of the bias, and a guide means for the To lead the feeder or the output of the recording material to or from the fixing structure lock in.

Of the Fixation structure may also be constructed to be between the release layer and the conductive one Layer of the fixing element by using the power source and the Resistive element provided with a potential difference to become. This makes possible, that a surface potential and an internal potential uninterrupted in the release layer generated at the time of fixation, and is preferred with the offsetting and the smeared image with borders Avoid banding.

The Pressing element may have any shape without any particular limitation, as long as there is the fixing gap between it and the fixing one Element can produce, and the recording material in such a Extent in Make press contact with the fixing element at the fixing gap That is, the toner can sufficiently pass through the recording material the fixing can be fixed. Such a pressing element can z. B. be pressed by pressure against the fixing, by pressing with a spring element such as a coil spring is generated, or by pressure, by the elasticity of a spongy, elastic, formed by using a resin or rubber body is produced. The pressing of the pressing element can, for example controlled by controlling a pressing force of a pressing means, or by adjusting the relative positional relationship to the fixing element.

The image forming apparatus of the present invention is an image forming apparatus having the above-described fixing structure, and may have any shape without any particular limitation, as long as it is an image forming apparatus having an image bearing member for carrying thereon an electrostatic latent image electrostatically charging the surface of the image bearing member, means for generating an electrostatic latent image for forming an electrostatic latent image on the surface of the thus charged image the element, developing means having a developer, and by which the electrostatic latent image formed on the image bearing member is developed to form a toner image, transfer means for transferring the toner image to a recording material, and a fixing structure by which The toner image transferred and unfixed to the recording material is fixed to form a fixed image.

When in the image forming apparatus of the present invention used imaging method, a system can be used in which an electrostatic latent image is developed with a developer is to create a toner image, and this toner image on a Recording material is fixed. As the image-forming method of such a system conventional known image-forming systems are used, as exemplified personified through an electrophotographic system in which an electrostatic latent image is made on an image-bearing element To be held, the electrostatic latent image with a developer is developed to produce a toner image, this toner image transferred to a recording material and the toner image transferred to the recording material by means of a fixing structure is fixed, and an electrostatic recording system, in which an electrostatic latent image on a recording material is formed, the electrostatic latent image with a developer is developed to produce a toner image and this toner image is fixed on the recording material.

The The image-forming apparatus of the present invention may be any Have shape with a structure that is sufficient or preferred to perform the image-forming system described above. Everyone conventional Known construction can be used in variety as such a construction become.

The The present invention will be described below by way of given examples described and with reference to the accompanying drawings. The present The invention is by no means restricted to the following examples.

example 1

Example 1 of the present invention will be described with reference to 1 and 2 described. 1 Fig. 12 is a schematic side view of an image forming apparatus in Example 1 of the present invention.

The image-forming apparatus of the present example is an image-forming apparatus of an electrophotographic system. It has a photosensitive drum 1 which is an image-bearing member holding an electrostatic latent image on its surface; a boosting construction 2 charging means for uniformly charging the photosensitive drum 1 is; an exposure device 3 which is means for generating an electrostatic latent image for exposing the thus charged photosensitive drum 1 to light to create the electrostatic latent image; a developing structure 4 as a developing means for supplying a toner of a developer to the photosensitive drum 1 to visualize the electrostatic latent image; a transfer roller 6 which is a transferring means for transferring a toner image, the visualized electrostatic latent image, onto a recording material 21 like paper; a register roller 5 which is a recording material conveying means consisting of a pair of rollers, and which intermeshes the recording material to the transfer roller 6 transported; a blade 7 comprising a cleaning means for removing transfer residual toner after transfer to the photosensitive drum 1 remains; a transport system 8th for transporting the recording material 21 holding the toner image thereon, to the next stage; and a fixing structure 20 which is a roller-type heat-fixing structure for fixing the toner image on the recording material 21 ,

2 Fig. 12 is a schematic view of the roll type heat fixing structure in the present example.

The fixing structure 20 has a fuser roller 10 and a press roll 11 which are provided in press contact with each other about a fixing gap 31 to form, and a resistance element 13 that is between a power source 12 and the fixer roller 10 is provided to connect both. On the side upstream of the fixing gap 31 is an entrance guide plate 9 provided the position at which the recording material in the fixing gap 31 enters, sets to prevent the paper from crumpling. On the side downstream of the fixing gap 31 is a transfer roller 16 provided to the recording material 21 from the fixing gap 31 to a paper output shaft (not shown) to lead. The transfer roller 16 is made of a conductive plastic, and is grounded.

The fixing roller 10 is constructed as explained below.

The fixing roller 10 includes z. B. an aluminum cylinder 10a with an outer diameter of 30 mm and a wall thickness of 2 mm, and above, in a thickness of about 10 μm, a release layer 10b provided, which is made of a fluorine resin. Inside, a halogen heating element (not shown) is also provided as a heating element, which is the fixing roller 10 under preset control so heated that it has an adequate temperature. The aluminum cylinder 10a continues with the bias power source 12 connected so that a voltage of -500 V from the bias current source 12 can be created.

The release layer 10b For example, a layer formed of polytetrafluoroethylene copolymer (PTFE) and a perfluoroalkoxytetrafluoroethylene copolymer (PFA) having excellent releasability behavior mixed in a ratio of 7: 3.

More specifically, the release layer is 10b a layer that is about 10 μm thick by dip coating the aluminum cylinder 10a with an aqueous dispersion (water-based dispersion), followed by drying and then baking; the aqueous dispersion is prepared by mixing the PTFE and the PFA in a ratio of 7: 3 and then mixing with 30% by weight of moderate resistance titanium oxide particles. As the titanium oxide particles, titanium oxide particles having an average particle diameter of 0.4 μm and having their surfaces subjected to hydrophilic treatment with Al ₂ O _{3 were} used. The present titanium oxide particles had a powder resistance of 0.9 × 10 ⁹ Ωcm.

The release layer 10b controls the surface resistance of the fixing roller 10 with the aid of the titanium oxide particles dispersed in the copolymer mixture. The surface resistance and the volume resistivity of this fixing roller 10 were measured to find that the surface resistance was 1.5 × 10 ⁷ Ω and the volume resistivity was 8.2 × 10 ¹³ Ωcm.

The press roll 11 has an outer diameter of 24 mm and includes a mandrel 11a of 12 mm outside diameter, and above provided an elastic layer 11b formed of a conductive silicon sponge; wherein the press roll is in press contact with the fuser roll 10 is provided to the fixing gap 31 to be formed to an extent necessary to provide a sufficient amount of heat for fixing. Likewise, the press roll has 11 an outermost layer consisting of a 30 μm thick PFA tube 11c is formed to be improved in releasability.

The image forming apparatus in the present example, as below described, driven and operated.

The photosensitive drum 1 becomes uniform by means of the charging assembly 2 charged, and a latent image is formed on the surface of the photosensitive drum 1 over the exposure device 3 educated. This latent image is created by means of the developing assembly 4 is reverse-processed with a negatively chargeable toner and is visualized as a toner image. Thereafter, the toner image is formed by the transfer roller 6 on the recording material 21 transferred by the register roller 5 transported in between. Thereafter, the photosensitive drum 1 through the blade 7 cleaned and ready for the next steps of imaging.

Meanwhile, the recording material goes through 21 , which carries the toner image on it, by transfer the transport system 8th and the entrance guide plate 9 , and becomes the part between the fixing roller 10 having inside it a heating source (not shown) and the press roll 11 where it is heated and pressed while being transported therebetween via the fixing nip between the two rollers, thus fixing the toner image.

In the fuser roller 10 For example, the above-mentioned heater-halogen heater (lamp) is electrified by a power source, so that the heat necessary for melting the toner on the recording material 21 is sufficient, from the inside of the aluminum cylinder 10a can be applied.

Anti-offset properties and resistance to smeared image with edges with banding were achieved using the fixture design 20 with the fuser roller 10 rated. As a pattern For evaluating the resistance to smeared image with edges with banding, a test pattern was used in which a horizontal line image having a four-dot width of 600 dpi was repeatedly drawn at intervals of 27 dots. Also, as a pattern for evaluating the anti-offset characteristics, a test pattern was used in which a vertical line image having a four-dot width of 600 dpi was repeatedly drawn at intervals of 27 dots. Also, as practical images, images using a pattern with a table and a photographic image in combination were reproduced. As a result, good results were obtained both in terms of anti-offset properties and resistance to smeared image with streaked edges. The reason why such good results were obtained is attributed to the fact that the surface potential in the release layer 10b was made low and the internal potential in the release layer 10b was maintained. This mechanism will be described below.

As the surface potential in the fixing member of the present invention lowers, referring to FIG 8th described. As in 8th shown causes any accumulation of electrical charges on the surface of the fixing roller 10 an insulation failure between the medium-resistance particles in the release layer 10b and the surface of the release layer so that the leaks at which the intermediate resistance particles nucleate are formed. This occurs because the release layer has a volume resistivity of 1 × 10 ¹⁴ Ωcm or more, and is substantially perfectly insulating, while the middle resistance particles have a resistance lower than the insulating properties, and have a low resistance is enough to cause a difference in resistance from that of the release layer, and thus the electric charges tend to flow to the part of the intermediate resistance particles.

This leaves the release layer 10b have a low surface potential at the part where the medium-resistance particles are nucleated, and brings with it the effect, the total surface potential of the release layer 10b to humiliate. This appears as the lowering of the surface resistance of the release layer 10b ,

In order to the intermediate resistance particles have the effect of leaking To form sites, it is advantageous that their particle diameter as big as possible is. Even if their primary particles have a small diameter, they can have the same effect achieve if their secondary particles a sufficiently large one Have diameter.

The insulation failure that can be attributed to the medium-resistance particles occurs at the surface of the release layer 10b , and thus it only lowers the surface potential of the release layer 10b , and does not affect too much the volume resistivity of the release layer 10b , In this way, the volume resistivity of the release layer 10b maintained at a prescribed value.

Furthermore have the titanium oxide particles used in the present example Surfaces, which has preferably been exposed to a hydrophilic treatment are. This hydrophilic treatment of the surface allows ions to be trapped on the particle surfaces be to enable that electric charges move easily. Thus this treatment has the function, the surface resistance on to humiliate.

Example 2

In the present example, zinc oxide whiskers subjected to hydrophilic treatment with alumina (Al ₂ O ₃ ) as in Example 1 are used as the middle resistance whiskers.

The Zinc oxide whiskers used in the present example are those with a length of 10 μm and an aspect ratio (Relationship the length to the width) of 20. Needle-shaped fillers with a high aspect ratio like the zinc oxide whiskers used here can the leaks make more readily than spherical particles, and their addition in an amount of about a half the spherical one Particles have the same effect. Thus, by their Add in a smaller amount the same effect can be achieved.

The zinc oxide whiskers used in the present example had a powder resistance of 1.8 × 10 ⁸ Ωcm. In the present example, a fuser roll 10 in the same manner as in Example 1, except that the zinc oxide whiskers were dispersed in an amount of 15% by weight. Of the Surface resistance and volume resistivity of this fixing roller 10 were measured to find that the surface resistivity was 9.9 × 10 ⁷ Ω and the volume resistivity was 1.7 × 10 ¹³ Ωcm.

This fixing roller 10 was set in the same fixing structure as that in Example 1, and the anti-offset properties and smeared image with edges with banding were evaluated in the same manner as in Example 1. As a result of the evaluation using the test patterns, the electrostatic offset in all cases slightly occurred because of a surface resistance which became larger than in Example 1, but was in a degree that offered no problem in the evaluation using the practical images. A smeared image with edges with banding was also present to an extent that offered no problem.

Comparative Example 1

in the Carbon black Ketjen Black was used as a conductive particle in the present comparative example instead of the medium-resistance particles used in Example 1 used.

In the present comparative example, a fixing roller was used 10 in the same manner as in Example 1, except that Ketjen Black was dispersed in an amount of 3% by weight. The surface resistance and the volume resistivity of this fixing roller 10 were measured to find that the surface resistivity was 7.7 × 10 ⁵ Ω and the volume resistivity was 1.3 × 10 ⁷ Ωcm. The Ketjen Black had a powder resistivity of less than 1.0 × 10 ⁰ Ω.

This fixing roller 10 was set in the same fixing structure as that in Example 1, and anti-offset properties and smeared image with streaked edges were evaluated in the same manner as in Example 1. As a result, the offset was not in a preferable degree, and even occurred in a degree that was recognizable in practical images. This is because the Ketjen Black, when dispersed even in a small amount, causes a large change in resistance, so that surface resistance in some parts does not sufficiently lower in minute regions, and therefore, even when observed, That the surface resistance is reduced as a whole, the surface is electrically charged to some part to attract the toner.

In addition, when the fixing roller of Comparative Example 1 was used, a smeared image with edges of streaking occurred to a serious degree, and even in the practical images, occurred in an intolerable degree. This is the case because of the volume resistivity of the fuser roller 10 has decreased, and therefore has increased the safety resistance assigned voltage, so that the opposite of the fixing roller 10 and the back of the recording material 21 generated electric field has been weakened.

Comparative Example 2

As in Comparative Example 1, Ketjen Black was used as the conductive particles. In Comparative Example 2, a fixing roller was used 10 in the same manner as in Example 1, except that Ketjen Black was dispersed in an amount of 1.5% by weight. The surface resistance and the volume resistivity of this fixing roller 10 were measured to find that the surface resistivity was 1.2 × 10 ⁸ Ω and the volume resistivity was 9.9 × 10 ⁷ Ωcm.

This fixing roller 10 was set in the same fixing structure as that in Example 1, and the extent to which offset and smeared image with banding edges occurred was examined. As a result, a smeared image with fringing edges occurred to a degree within the tolerance, that is, to such a degree that a smeared image with fringing edges was recognizable in the test patterns but was less conspicuous in the practical images. However, the offset occurred to a serious degree, so that it was even recognizable in the practical images. This is because the Ketjen Black, if dispersed even in a small amount, causes the volume resistivity to be lowered to some degree but not to form leaks, and therefore the surface resistance does not lower and the surface area decreases the fixing roller is charged electrically.

Comparative Example 3

In Comparative Example 3, the same aluminum cylinder as that used in Example 1 was used as a conductive substrate, and a release layer of a multi-layer structure was formed over it. 9 is a schematic sectional view of a fixing member of Comparative Example 3.

As in Example 1, the aluminum cylinder 10a with an aqueous dispersion (water-based dispersion) dip-coated in a thickness of about 40 microns, followed by drying and then baking to a first release layer 10c to build; the aqueous dispersion was prepared by mixing PTFE and PFA in a ratio of 7: 3, and further blending with 30 weight percent titanium oxide particles as intermediate resistance particles. On this layer 10c The same aqueous dispersion as the above except that 10% by weight of titanium oxide particles were further dispersed therein was dip-coated in a thickness of about 10 μm, followed by drying and then baking to form a second release layer 10d to build.

Thus, in Comparative Example 3, the release layer was formed in a thickness of 50 μm in total for the first release layer 10c and the second release layer 10d , The surface resistance and the volume resistivity of the fixing roller of Comparative Example 3 were measured to find that the surface resistivity was 1.7 × 10 ¹³ Ω and the volume resistivity was 4.4 × 10 ¹⁴ Ωcm.

These Fuser roller was in the same Fixieraufbau as in Example 1 inserted, and degrees where the offset and the smeared image with edges with Streaking were studied. As a result, that was smeared image with edges with banding in a degree within tolerance before and offered no problem. However, the offset was in a serious Degree before, so he even recognizable in the practical images was. This is the case because it's in a double-layer arrangement formed release layer makes it difficult to leaks in the release layer are formed, and in addition, titanium oxide particles dispersed in a small amount in the second release layer, and thus, the surface resistance does not lower, and the surface the fixing roller is charged electrically.

Comparative Example 4

A fuser roller 10 was prepared in the same manner as in Example 1 except that the release layer was formed in a thickness of 50 μm. The surface resistance and the volume resistivity of this fixing roller 10 were measured to find that the surface resistivity was 1.2 × 10 ⁸ Ω and the volume resistivity was 3.9 × 10 ¹⁴ Ωcm.

These Fuser roller was in the same Fixieraufbau as in Example 1 inserted, and degrees where offset and a smeared image with edges with banding were investigated. As a result There was a smeared image with edges with banding in a degree within tolerance before and offered no problem. However, the offset was in a serious Degree before, so he even recognizable in the practical images was. This is because it is the release layer formed in a large thickness complicates leaks in the release layer form, so that the surface resistance does not degrade and the surface the fixing roller is electrically charged.

The results of the foregoing Examples 1 and 2 and Comparative Examples 1 to 4 are shown in Table 1. Table 1 example Comparative example 1 2 1 2 3 2 Surface resistance (Ω): 1.5 × 10 ⁷ 9.9 × 10 ⁷ 7.7 × 10 ⁵ 1.2 × 10 ⁸ 1.7 × 10 ¹³ 1.2 × 10 ⁸ Volume resistance (Ωcm): 8.2 × 10 ¹³ 1.7 × 10 ¹³ 1.3 × 10 ⁷ 9.9 × 10 ⁷ 4.4 × 10 ¹⁴ 3.9 × 10 ¹⁴ Anti-offset properties: * 1 A B C C C C resistance across from one smeared Picture with Edges with Banding: * 2 A A C B A A

- Evaluation criteria -

* 1 (Anti-offset properties):

• A: no problem, even in test patterns.
• B: not noticeable in practical pictures.
• C: clearly visible, even in realistic pictures.

* 2 (resistance to one smeared image with edges with banding:

• A: no problem, even in test patterns.
• B: not noticeable in practical pictures.
• C: clearly visible, even in realistic pictures.

As can be seen from these results, it can be said that preferred properties for the fuser roll 10 are necessary, the surface resistance is 1.0 × 10 ⁸ Ωcm or less and the volume resistivity is 1.0 × 10 ⁸ Ωcm or more. Also, when the conductive particles having a low resistance as in Comparative Examples 1 and 2 are used, it is difficult to control the surface resistance and the volume resistivity within the desired range. Also, the releasing layer of the double layer structure as in Comparative Example 3 and the release layer with a large thickness as in Comparative Example 4 can not efficiently generate leaks, and an appropriate surface resistance and volume resistivity are not obtained. On the other hand, dispersing the medium-resistance particles or the intermediate-resistance whiskers in the release layer as in the present invention enables stable control of the surface resistivity values without lowering the volume resistivity, making it possible to provide a fixing roller that can handle both the anti-offset Properties as well as the resistance to a smeared image with edges having banding has been provided.

In The foregoing examples and comparative examples are the fixing structure is constructed such that a fixing bias on the hollow mandrel of Fixing roller is applied. Also in the systems where one such Fixiervorspannung is not applied, may be a charge tiny regions as a result of paper feeding, as in the case of fuser rollers with release layers containing only Ketjen Black has been dispersed, and the toner can be attracted to the roll surface to cause offset. Accordingly, even in such systems, where the Fixiervorspannung is not applied, the fixing of the present invention in which the medium-resistance particles or whiskers are dispersed in the release layer, also as a countermeasure for the electrostatic offset effective.

Example 3

A fixing structure in the present example is a heat fixing structure characterized by applying a heat fixing method of a thermal fixing system of the film type in which toner images are fixed on recording materials via a film interposed between a heating zone and a press roller to minimize powder consumption, without supplying electric power to the heat fixing structure, particularly when he is in stand-by mode.

3 schematically illustrates the structure of such a heat fixing structure of a film heat fixing system.

The fixing structure of the present example has, as in 3 shown a stander (a carrier) 62 , a heating element (hereinafter "heating resistor") 61 stationary on the stand-up 62 is worn, a press roll 11 which is a press member held in press contact via a pressing means (not shown, eg, an elastic member such as a spring pressed against a fixing member), a thin-thickness film (hereinafter "fixing film"). ) 63 which is a heat-resistant fixing member, and a temperature-detecting device 64 that is the temperature of the heating resistor 61 detected. A gap 31 (fixing gap 31 ) is formed in a fixed width to the fixing film 63 between the heating resistor 61 and the press roll 11 insert.

In the heating resistor 61 As a heating element usually a ceramic heating resistor is used. This ceramic heating resistor comprises an electrically insulating, good thermally conductive ceramic substrate with low heat capacity, eg. As aluminum, on the surface (on the side of the fixing film 63 opposite) an electrification heat generation resistance layer such as a silver-palladium (Ag / Pd) layer or a tantalum nitrite (Ta ₂ N) layer by screen printing across the longitudinal direction (the direction vertical to the drawing surface) of the substrate, and the surface of the heat-generating resistor layer is further covered with a glass protective layer of thin thickness.

The stand-up holder 62 is z. B. formed from a heat-resistant plastic element. It avoids that heat in the direction that the fixing gap 31 is opposite, escapes, keeps the heating resistor 61 and also serves as a transport guide of the fixing film 63 ,

The fixing film 63 is transported in the direction of an arrow and moved by a driving means (not shown) or a rotational force of the press roller 11 Slidable in close contact with the surface of the heating resistor and the surface of the press roll 11 at the fixing gap 31 emotional.

The fixing film 63 is an element in the form of a cylinder, an endless belt or a roller-type continuous web. The fixing film 63 is formed in a thickness of 20 to 70 microns, so that the heat of the heating resistor 61 to a heating target recording material in good efficiency.

The fixing film 63 will be in sliding contact with the heating element 61 rotated, and therefore, any frictional resistance between the fixing film and the heating resistor must be made small. Accordingly, a lubricant such as grease having a high heat resistance becomes between the fixing film 63 and the heating resistor 61 and between the fixing film 63 and the surface of the stand 62 which remain in contact with the former, remain applied.

4 illustrates the structure of the fixing film 63 (cylindrical).

The fixing film 63 is made up of three layers, a film base layer 63a , a conductive primer layer 63b and a release layer 63c , The film base layer 63a stands on the side of the heating resistor, and the release layer 63c on the side of the press roll.

The film base layer 63a is made of high-insulating polyimide, polyamide-imide or PEEK (polyether ether ketone), has heat resistance and high elasticity, has a thickness of 15 to 60 μm, and retains mechanical strength against the tearing force of the entire fixing film 63 ,

The conductive primer layer 63b is formed by dip-coating a dispersion mixture of a polyamide resin and a fluorine resin containing carbon black dispersed therein, and is a thin layer having a thickness of 2 to 6 μm. The conductive primer layer 63b is connected to a bias current source (not shown), and a DC voltage of z. B. -500 V is applied so that an electric field ge opposite the fixing film 63 and the back of the recording material can be produced.

The release layer 63c is formed as in Example 1 by dip-coating an aqueous dispersion prepared by mixing PTFE and PFA in a ratio of 7: 3 and further dispersing 30% by weight of the same titanium oxide particles as those in Example 1 which has been subjected to hydrophilic treatment Alumina have been exposed. The surface resistance and the volume resistivity of this fixing film were measured to find that the surface resistance was 1.5 × 10 ⁷ Ω and the volume resistivity was 8.2 × 10 ¹³ Ωcm.

The heating resistor 61 is heated by electrification of the electrification heat generation resistance layer, whereupon the electrification heat generation resistance layer generates heat, and the entire heating resistance including the ceramic substrate and the glass protection film are rapidly heated. The supply of electricity to the electrification heat generation resistance layer is controlled so that the heating resistance temperature for which the temperature rise of this heating resistance 61 by the temperature detection device 64 is detected, can be maintained at a substantially constant temperature (fixing temperature). Thus, the heating resistor 61 through the heating resistor 61 heated and temperature controlled at a fixed fixing temperature.

In the state where the fixing film 63 is transported in the direction of the arrow and moved while the heating resistor 61 is heated and controlled at a predetermined temperature, a heating target recording material on which unfixed toner images have been formed and held is interposed between the fixing film 63 and the press roll at the fixing gap 31 where the recording material intervenes through the fixing gap 31 together with the fixing film 63 and in close contact with the surface of the fixing film 63 is transported.

At this fixing gap, the recording material and the toner image with the heating resistor 61 over the fixing film 63 heated, and the toner image on the recording material is heat-set. At the part which has passed the fixing nip, the recording material comes off the surface of the fixing film 63 separated and is transported on.

Under Use of the fixing structure of the present example has been Grade, which involves offset and a smeared image with edges Streaking, in the same manner as in Example 1 examined. As a result, good results were obtained in all cases.

As described above, the fixing member of the present invention has the conductive layer and the release layer formed on the conductive layer, and, in the release layer, the middle resistance particles and / or intermediate resistance whiskers are dispersed, the release layer being so formed to have a surface resistance of 1.0 × 10 ⁸ Ω or less, and a volume resistivity of 1.0 × 10 ⁸ Ωcm or above. Thus, the part of the medium resistance particles and / or the middle resistance whisker serves as leaks, which can lower the surface resistance of the fixing member to a degree within a specific range, and also can not make its volume resistivity unnecessarily small to within of a specific area without dispersing a conductive substance or antistatic substance in the releasing layer of the fixing structure. Thus, the fixing member can be provided which has superior anti-offset properties and resistance to smeared image with edges with banding.

In the fixing member of the present invention, the middle resistance particles and the middle resistance whiskers may have a powder resistance of 1.0 × 10 ¹ to 1.0 × 10 ¹² Ωcm. Thus, the part of the intermediate resistance particles and / or the middle resistance whisker serves as leaks which can lower the surface resistance of the fixing member and also can not make its volume resistivity unnecessarily small without dispersing a conductive substance or antistatic substance in the release layer of the fixing assembly. This is more effective for forming leaks in good efficiency and independently controlling the surface resistance and volume resistivity of the release layer when the fixing member having improved anti-offset characteristics and smeared image with edges with banding is provided.

In the fixing member of the present invention, the middle resistance particles and the intermediate resistance whiskers may have a powder resistance of 1.0 × 10 ³ to 1.0 × 10 ⁹ Ωcm. Thus, the portion of the medium resistance particles and / or the medium resistance whisker is leaking Sites which can lower the surface resistance of the fixing member and also can not make its volume resistivity unnecessarily small without dispersing a conductive substance or antistatic substance in the release layer of the fixing structure.

This is much more effective for the formation of leaks in a good efficiency and for independent taxes of surface resistance and the volume resistivity of the release layer when the fixing element with improved anti-offset properties and durability across from a smeared image with edges is provided with banding.

In the fixing element of the present invention, the particles with medium Resistance and the whiskers having medium resistance surfaces, which have been exposed to a hydrophilic treatment. This makes possible, that ions on the particle surfaces or whisker surfaces and be caught in their neighborhood to the surface resistance to degrade more effectively, and is more effective for providing of the fixing element, which has both anti-offset properties, as well Resistance to one smeared image with edges has achieved with banding.

In the fixing element of the present invention, the whiskers with medium Resistance Whisker to be made of a metal oxide. This can be the strength improve the release layer of the fixing and can simultaneously the durability across from To improve wear. This is thus more effective for providing the fixing element with superior Anti-offset properties and resistance to smeared Picture with borders with banding.

In the fixing element of the present invention, the whiskers with medium Resistance to be metal oxide whiskers whose surfaces undergo a hydrophilic treatment have been suspended. This is much more effective for providing of the fixing with superior Anti-offset properties and resistance to one smeared image with edges with banding.

In the fixing element of the present invention, the particles with medium Resistance titanium oxide particles whose surfaces of a hydrophilic treatment have been suspended. This is much more effective for providing of the fixing with superior Anti-offset properties and resistance to one smeared image with edges with banding.

In the fixing element of the present invention, the particles with medium Resistor and / or the medium resistance whiskers in the Release layer in a total amount of 5 to 50 wt .-% based be contained on the weight of the release layer. This is much more effective for providing the fuser member having both anti-offset properties, as well as durability across from a smeared image with edges has achieved with banding.

In the fixing element of the present invention, the release layer one or both of the medium resistance particles and the Whisker with medium resistance and a fluorine resin included. This is much more effective for improving release properties and durability across from Heat, if the fixing element, which has both anti-offset properties as well resistance across from a smeared image with edges achieved with banding is provided.

In the fixing member of the present invention, the release layer may be formed to have a surface resistance of 1.0 × 10 ³ to 1 × 10 ⁸ Ω and a volume resistivity of 1 × 10 ⁸ to 1 × 10 ¹⁵ Ωcm. This is much more effective for providing the fuser which has achieved both anti-offset properties and resistance to smeared streaked edges.

In the fixing element of the present invention, the release layer a layer thickness of 1 to 45 microns exhibit. This is much more effective for achieving both Resistance, as well as heat efficiency of the fixation structure when the fixing element, which has both anti-offset properties as well as durability across from a smeared image with edges achieved with banding is provided.

In the fixing element of the present invention, the release layer a layer thickness of 3 to 30 microns exhibit. This is much more effective for forming a fixation structure with a good heat efficiency and is advantageous for making the device compact when the fixing element, which has both anti-offset properties as well resistance across from a smeared image with edges achieved with banding is provided.

The Fixing element of the present invention may take the form of a Roller are formed. This is much more effective for achieving a higher process speed the device when the fixing element, both anti-offset properties as well as durability across from a smeared image with edges achieved with banding is provided.

The Fixing element of the present invention may take the form of a Roller are formed. This is much more effective for providing the fixation element with a higher one Heat transfer efficiency, when the fuser, which has both anti-offset properties as also resistance across from a smeared image with edges achieved with banding is provided.

In The present invention is in the fixing structure with a fixing element and a pressing member that is in press contact with the fixing member comes to form a fixing nip where the recording material, on which an unfixed toner image has been formed guided the fixing gap is to the unfixed toner image on the recording material to fix a fixed image on the recording material to produce the Fixieraufbau characterized in that the fixing element the above-described special fixing element. As such a fixing provided, the fixation structure, which has both anti-offset properties, as well as durability across from a smeared image with edges achieved with banding.

In The fixation structure of the present invention may have a potential difference between the release layer and the conductive layer become. This is much more effective for providing the fixation structure, which has both anti-offset properties and durability across from a smeared image with edges has achieved with banding.

In The present invention is in the image forming apparatus with an image-bearing element, about it an electrostatic latent Picture, a charging device for electrostatic charging the surface the image-bearing element, one an electrostatic latent image generating device for generating an electrostatic latent image on the surface of the so charged image-bearing element, a developing device with a developer, and through that on the image-bearing element generated electrostatic latent image is developed to form a toner image to generate a transmission device for the transfer the toner image on a recording material, and a Fixieraufbau, by the toner image transferred to the recording material that does not fixed, fixed to produce a fixed image, the image-forming device characterized in that the Fixieraufbau is the above-described special Fixieraufbau. There such a fixing structure is provided, the image-forming Device that has both anti-offset properties as well as durability across from a smeared image with edges achieved with banding.

Claims (24)

A fixing member for use in a fixing structure, wherein the fixing structure has at least the fixing member and a pressing member which comes into pressure contact with the fixing member to form a fixing nip, whereby a recording material holding an unfixed toner image thereon is passed through the fixing nip to fix the unfixed toner image to the recording material to form a fixed image on the recording material; the fixing element is a conductive layer ( 10a ) and a release layer formed on the conductive layer ( 10b characterized in that medium resistance particles are dispersed in the release layer, the intermediate resistance particles having surfaces which have been subjected to hydrophilic treatment such that the release layer has a surface resistance of 1.0 x 10 ⁸ Ω or less and has a volume resistivity of 1.0 × 10 ⁸ Ω · cm or more. A fixing member for use in a fixing structure, wherein the fixing structure has at least the fixing member and a pressing member which comes into pressure contact with the fixing member to form a fixing nip, whereby a recording material holding an unfixed toner image thereon is passed through the fixing nip so that the unfixed toner image is fixed to the recording material to form a fixed image on the recording material; the fixing element is a conductive layer ( 10a ) and a release layer ( 10b ) formed on the conductive layer, characterized in that Intermediate resistance whiskers are dispersed in the release layer, the intermediate resistance whiskers having surfaces which have been subjected to hydrophilic treatment so that the release layer has a surface resistance of 1.0 x 10 ⁸ Ω or less and a volume resistivity of 1 , 0 × 10 ⁸ Ω · cm or more. A fuser member according to claim 1, wherein said intermediate resistance particles have a powder resistance of 1.0 x 10 ¹ Ω · cm to 1.0 x 10 ¹² Ω · cm. A fixing member according to claim 3, wherein said medium-resistance particles have a powder resistance of 1.0 × 10 ³ Ω · cm to 1.0 × 10 ⁹ Ω · cm. The fuser member of claim 2, wherein the intermediate resistance whiskers have a powder resistance of 1.0 x 10 ¹ Ω · cm to 1.0 x 10 ¹² Ω · cm. The fuser member of claim 5, wherein the intermediate resistance whiskers have a powder resistance of 1.0 x 10 ³ Ω · cm to 1.0 x 10 ⁹ Ω · cm. Fixing element according to claim 1, wherein the particles with medium resistance are titanium oxide particles whose surfaces are one hydrophilic treatment have been exposed. Fixing element according to claim 7, wherein the particles with medium resistance are titanium oxide particles whose surfaces are one hydrophilic treatment with alumina have been exposed. Fixing element according to claim 2, wherein the whiskers with medium resistance surfaces possess exposed to a hydrophilic treatment with alumina have been. Fixing element according to claim 2, wherein the whiskers whisker of a metal oxide are medium resistance. Fixing element according to claim 1 or 2, wherein the Medium-resistance particles or medium-sized whiskers Resistance in the release layer in an amount of 5% by weight to 50% by weight based on the weight of the release layer are included. Fixing element according to claim 11, wherein the particles medium resistance or medium resistance whiskers in the release layer in an amount of 10% by weight to 40% by weight are contained based on the weight of the release layer. Fixing element according to claim 1 or 2, wherein the Release layer, the medium-resistance particles or the Whisker with medium resistance, and contains a fluororesin. Fixing element according to claim 1 or 2, wherein the release layer has a surface resistance of 1.0 × 10 ³ Ω to 1 × 10 ⁸ Ω and a volume resistivity of 1.0 × 10 ⁸ Ω · cm to 1.0 × 10 ¹⁵ Ω · cm owns. Fixing element according to claim 1 or 2, wherein the Release layer has a layer thickness of 1 .mu.m to 45 .mu.m. Fixing element according to claim 15, wherein the release layer a layer thickness of 3 microns has up to 30 microns. Fixing element according to claim 1 or 2, which has the shape a roller has. Fixing element according to claim 1 or 2, which has the shape a belt possesses. Fixing element according to claim 1 or 2, which has the shape owns a movie. Fixing element according to claim 1 or 2, which is a fixing roller is. A fixing assembly comprising a fixing member as defined in any one of claims 1 to 20, and a pressing member which press-contacts with the fixing member to form a fixing nip, wherein; a recording material holding thereon an unfixed toner image is passed through the fixing gap, such that the unfixed toner image is fixed to the recording material to form a fixed image on the recording material. Fixing structure according to claim 21, wherein the fixing element a fixing roller and the pressure element is a pressure roller. Fixing structure according to claim 21, wherein the fixing element a fixing film and the printing element is a pressure roller. An image forming apparatus, comprising: an image-bearing Element to hold thereon an electrostatic latent image; a Charging device to the surface of the image bearing element electrostatically charged; an electrostatic latent one Image generating device for generating an electrostatic latent image on the surface of the thus charged image bearing member; a development facility with a developer, and through that on the image-bearing element generated electrostatic latent image is developed to form a toner image to create; a transmission device, to transfer the toner image to a recording material; and a fixing structure through which transferred to the recording material and unfixed permanent toner image is fixed to a fixed one To create an image; wherein the fixing structure of the fixing structure according to one of the claims 21 to 23 is.